Using the in-game Editor I now have 51 more scenarios which I can play either side. Also adjusted the Scenario Parameters for balance.
I would be willing to share the file ( not very big, less then 8mb unzipped ) if it is legal to do so. Without the DLC's I doubt they would work.
The DLC's edited are:
Blood Angels (10)
Golgotha (10)
Orc Hunters (10)
Salamanders (10)
Ultra Marines (11)

Well, it appears I "jumped the gun" a little. Not all the scenarios allow me to play both sides. Some of the scenarios allow me to take my 1st turn with the Orcs then after ending it, goes directly to the "defeat screen". However, I am able to play numerous ones with the Orcs. It must have something to do with the Victory Conditions per each scenario. I shall be investigating this using the editor. Will post any news.

I think I found the issue with the scenarios that do not work, as per allowing either side to be played. Some of the scenarios have the "side 1" ( non Orcs ) having to purchase their initial units. The AI does not do this, evidently. Thus ending the game on the 1st turn.
I will share the adjusted base "whscn files" if it is legal to do so.
I also, edited the original scenarios in the "data" folder for a total of 83 adjusted scenarios.